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Author: search.filters.author.Kaewpanha, MalineeStart date: 2020

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Now showing 1 - 4 of 4
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    Microencapsulation of lemongrass oil by spray drying: Role of emulsion size, oil loading, and inlet air temperature on flavor retention and release kinetics
    (2026-03-01)
    Paiboon, Narin
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    Kaewpanha, Malinee
    ;
    Ruktanonchai, Uracha Rungsardthong
    ;
    Yoshii, Hidefumi
    ;
    Soottitantawat, Apinan
    Microencapsulation of lemongrass oil using modified starch (Capsul®) was investigated via spray drying to interpret the process–structure–transport relationships governing flavor retention and release. The effects of oil loading, emulsion size, and inlet air temperature on emulsion characteristics, citral retention, powder morphology, and stability were evaluated. Increasing oil content resulted in larger emulsion droplets, reduced emulsification efficiency, and greater surface oil content, leading to lower citral retention. Capsul® demonstrated high encapsulation performance, retaining up to 40 wt% lemongrass oil with minimal losses. Emulsion droplet size emerged as a key structural determinant, with smaller droplets yielding superior retention and reduced surface oil. By integrating microstructural analysis with kinetic modeling, this study demonstrates that drying-induced particle architecture, rather than retention efficiency alone, governs long-term stability. Release profiles were well described by Avrami kinetics, confirming diffusion-controlled transport, with larger droplets and higher oil loading exhibiting increased effective diffusivity. Although inlet air temperature had minimal influence on immediate citral retention, it strongly affected powder microstructure: higher temperatures produced larger particles with thinner walls, whereas temperatures below 140 °C increased residual moisture, lowered glass transition temperature, and accelerated volatile release. These findings provide mechanistic guidance for the rational design and optimization of spray-drying processes to tailor the stability and release performance of encapsulated flavor systems.
      2
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    Valorization of horse manure conversion to magnetic carbon nanofiber for dye adsorption by hydrothermal treatment coupled with carbonization
    (2024-06-01)
    Kaewtrakulchai, Napat
    ;
    Chanpee, Sirayu
    ;
    Pasee, Warit
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    Putta, Ampol
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    Chutipaijit, Sutee
    Pollution of water resources has recently increased as a result of expanded industrial activity. Recycling waste biomass into bio-adsorbent material offers a cheap, easy, and eco-friendly solution. In this study, magnetic carbon nanofibers (MCNF) with a highly porous structure were developed from magnetite-preloaded horse manure by hydrothermal treatment followed by carbonization using different ratios of iron (III) nitrate and iron oxide as magnetic precursors. The produced MCNF had a very porous structure with specific surface area of 435.31 m<sup>2</sup>/g and high carbon content. The magnetic characteristics of MCNF promoted by the presence of iron oxide species. The saturated magnetization of MCNF obtained from a 5:5 ratio of the magnetic precursors (iron (III) nitrate: iron oxide) was 2.48 emu/g. Synthesized MCNF was applied as a bio-adsorbent for methylene blue (MB) removal from aqueous solution, with results showing excellent dye adsorption of 92–99 %. MB adsorption was facilitated by pore filling, electrostatic contact, hydrogen bonding, and ion complexation. Experimental results indicated that the Freundlich isotherm and pseudo-second-order kinetic models concurred with the observed MB adsorption data, suggesting that the adsorption mechanism involved multilayered micropore interactions between magnetite and MB chemisorption. The resulting magnetic adsorbent was successfully removed from the aqueous solution by physical separation. Findings indicated that horse manure-derived MCNF could be used as an efficient bio-adsorbent to remove organic contaminants in wastewater.
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    Effect of Nb doping on the structural, optical, and photocatalytic properties of SrTiO3 nanopowder synthesized by sol-gel auto combustion technique
    (2022-01-01)
    Nunocha, Pornnipa
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    Kaewpanha, Malinee
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    Bongkarn, Theerachai
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    Eiad-Ua, Apiluck
    ;
    Suriwong, Tawat
    Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi<inf>1−</inf><inf>x</inf> Nb <inf>x</inf> O<inf>3</inf> (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (E<inf>g</inf>). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, E<inf>g</inf>, Nyquist plot, and Mott-Schottky analyses.
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    Effect of sr substitution on structural, ferroelectric and magnetic properties of la1-xsrxfeo3 perovskite oxides
    (2020-01-01)
    Kaewpanha, Malinee
    ;
    Nunocha, Pornnipa
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    Bongkarn, Theerachai
    ;
    Eiad-Ua, Apiluck
    ;
    Suriwong, Tawat
    Effect of Sr substitution on structural, magnetic and electrical properties of LaFeO<inf>3</inf> perovskite oxides has been studied. Using the selected Sr doping content (x) from 0.0 to 1.0, perovskite La<inf>1-x</inf>Sr<inf>x</inf>FeO<inf>3</inf> nanopowder was synthesized by sol-gel auto-combustion method, followed by calcination at 900 °C for 2 h. The synthesized powder was pressed into disks at room temperature and then the disk samples were sintered at 1200 °C for 12 h to obtain a single-phase compound formation and uniaxial compaction. The influence of Sr doping on the phase formation, morphology, ferroelectric and magnetic properties was investigated. The phase formation of the sample changes from orthorhombic at low Sr doping through rhombohedral to cubic for Sr-rich sample as the stoichiometry approached SrFeO<inf>3</inf>. The grains of La<inf>1-x</inf>Sr<inf>x</inf>FeO<inf>3</inf> ceramics revealed an irregular polyhedron shape. SEM-EDS mapping analysis also exhibited the uniform distribution of all elements. The direct energy gap (E<inf>g</inf>) was found to decrease with increasing amounts of Sr doping. Moreover, the La<inf>0.6</inf>Sr<inf>0.4</inf>FeO<inf>3</inf> ceramic exhibited ferromagnetic behavior with saturated magnetization (M<inf>s</inf>) of 0.305 emu/g at room temperature.